“A battery prototype has been designed using salt water and materials that are non-toxic and charge quickly, paving the way for new types of battery.
The design principles behind the new prototype, which changes colour as it charges, could also be applied to existing battery technologies to create new devices for energy storage, biological sensing, and smart colour-changing materials…”
Source:
https://www.ecnmag.com/videos/2019/03/non-toxic-salt-water-battery-prototype-can-charge-seconds